lei: fix handling of broken lei.saved-search config files

lei shouldn't become unusable if a config file is invalid.
Instead, show the "git config" stderr and attempt to continue
gracefully.

Reported-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Link: https://public-inbox.org/meta/20210910141157.6u5adehpx7wftkor@meerkat.local/

6 files changed, 128 insertions, 74 deletions

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index b3e00ae0..74a1a6f5 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -164,12 +164,12 @@ sub config_fh_parse ($$$) {
 }
 
 sub git_config_dump {
-        my ($class, $file) = @_;
+        my ($class, $file, $errfh) = @_;
         return bless {}, $class unless -e $file;
         my $cmd = [ qw(git config -z -l --includes), "--file=$file" ];
-        my $fh = popen_rd($cmd);
+        my $fh = popen_rd($cmd, undef, { 2 => $errfh // 2 });
         my $rv = config_fh_parse($fh, "\0", "\n");
-        close $fh or die "failed to close (@$cmd) pipe: $?";
+        close $fh or die "@$cmd failed: \$?=$?\n";
         bless $rv, $class;
 }
 
diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index bbb6ab7e..0b4c99dc 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -1029,13 +1029,15 @@ sub path_to_fd {
 
 # caller needs to "-t $self->{1}" to check if tty
 sub start_pager {
-        my ($self) = @_;
+        my ($self, $new_env) = @_;
         my $fh = popen_rd([qw(git var GIT_PAGER)]);
         chomp(my $pager = <$fh> // '');
         close($fh) or warn "`git var PAGER' error: \$?=$?";
         return if $pager eq 'cat' || $pager eq '';
-        my $new_env = { LESS => 'FRX', LV => '-c' };
-        $new_env->{MORE} = 'FRX' if $^O eq 'freebsd';
+        $new_env //= {};
+        $new_env->{LESS} //= 'FRX';
+        $new_env->{LV} //= '-c';
+        $new_env->{MORE} = $new_env->{LESS} if $^O eq 'freebsd';
         pipe(my ($r, $wpager)) or return warn "pipe: $!";
         my $rdr = { 0 => $r, 1 => $self->{1}, 2 => $self->{2} };
         my $pgr = [ undef, @$rdr{1, 2} ];
@@ -1052,6 +1054,19 @@ sub start_pager {
         $self->{pgr} = $pgr;
 }
 
+# display a message for user before spawning full-screen $VISUAL
+sub pgr_err {
+        my ($self, @msg) = @_;
+        return $self->err(@msg) unless $self->{sock} && -t $self->{2};
+        start_pager($self, { LESS => 'RX' }); # no 'F' so we prompt
+        print { $self->{2} } @msg;
+        $self->{2}->autoflush(1);
+        my $pgr = delete($self->{pgr}) or return;
+        $self->{2} = $pgr->[2];
+        $self->{1} = $pgr->[1];
+        send($self->{sock}, 'wait', MSG_EOR); # wait for user to quit pager
+}
+
 sub stop_pager {
         my ($self) = @_;
         my $pgr = delete($self->{pgr}) or return;
diff --git a/lib/PublicInbox/LeiEditSearch.pm b/lib/PublicInbox/LeiEditSearch.pm
index 82dfbf63..47166ce7 100644
--- a/lib/PublicInbox/LeiEditSearch.pm
+++ b/lib/PublicInbox/LeiEditSearch.pm
@@ -8,20 +8,89 @@ use v5.10.1;
 use PublicInbox::LeiSavedSearch;
 use PublicInbox::LeiUp;
 
-sub lei_edit_search {
-        my ($lei, $out) = @_;
-        my $lss = PublicInbox::LeiSavedSearch->up($lei, $out) or return;
+sub edit_begin {
+        my ($lss, $lei) = @_;
+        if (ref($lss->{-cfg}->{'lei.q.output'})) {
+                delete $lss->{-cfg}->{'lei.q.output'}; # invalid
+                $lei->pgr_err(<<EOM);
+$lss->{-f} has multiple values of lei.q.output
+please remove redundant ones
+EOM
+        }
+        $lei->{-lss_for_edit} = $lss;
+}
+
+sub do_edit ($$;$) {
+        my ($lss, $lei, $reason) = @_;
+        $lei->pgr_err($reason) if defined $reason;
         my @cmd = (qw(git config --edit -f), $lss->{'-f'});
         $lei->qerr("# spawning @cmd");
-        $lss->edit_begin($lei);
+        edit_begin($lss, $lei);
         # run in script/lei foreground
         require PublicInbox::PktOp;
         my ($op_c, $op_p) = PublicInbox::PktOp->pair;
         # $op_p will EOF when $EDITOR is done
-        $op_c->{ops} = { '' => [$lss->can('edit_done'), $lss, $lei] };
+        $op_c->{ops} = { '' => [\&op_edit_done, $lss, $lei] };
         $lei->send_exec_cmd([ @$lei{qw(0 1 2)}, $op_p->{op_p} ], \@cmd, {});
 }
 
+sub _edit_done {
+        my ($lss, $lei) = @_;
+        my $cfg = $lss->can('cfg_dump')->($lei, $lss->{'-f'}) //
+                return do_edit($lss, $lei, <<EOM);
+$lss->{-f} is unparseable
+EOM
+        my $new_out = $cfg->{'lei.q.output'} // '';
+        return do_edit($lss, $lei, <<EOM) if ref $new_out;
+$lss->{-f} has multiple values of lei.q.output
+EOM
+        return do_edit($lss, $lei, <<EOM) if $new_out eq '';
+$lss->{-f} needs lei.q.output
+EOM
+        my $old_out = $lss->{-cfg}->{'lei.q.output'} // return;
+        return if $old_out eq $new_out;
+        my $old_path = $old_out;
+        my $new_path = $new_out;
+        s!$PublicInbox::LeiSavedSearch::LOCAL_PFX!! for ($old_path, $new_path);
+        my $dir_old = $lss->can('lss_dir_for')->($lei, \$old_path, 1);
+        my $dir_new = $lss->can('lss_dir_for')->($lei, \$new_path);
+        return if $dir_new eq $dir_old;
+
+        ($old_out =~ m!\Av2:!i || $new_out =~ m!\Av2:!) and
+                return do_edit($lss, $lei, <<EOM);
+conversions from/to v2 inboxes not supported at this time
+EOM
+        return do_edit($lss, $lei, <<EOM) if -e $dir_new;
+lei.q.output changed from `$old_out' to `$new_out'
+However, $dir_new exists
+EOM
+        # start the conversion asynchronously
+        my $old_sq = PublicInbox::Config::squote_maybe($old_out);
+        my $new_sq = PublicInbox::Config::squote_maybe($new_out);
+        $lei->puts("lei.q.output changed from $old_sq to $new_sq");
+        $lei->qerr("# lei convert $old_sq -o $new_sq");
+        my $v = !$lei->{opt}->{quiet};
+        $lei->{opt} = { output => $new_out, verbose => $v };
+        require PublicInbox::LeiConvert;
+        PublicInbox::LeiConvert::lei_convert($lei, $old_out);
+
+        $lei->fail(<<EOM) if -e $dir_old && !rename($dir_old, $dir_new);
+E: rename($dir_old, $dir_new) error: $!
+EOM
+}
+
+sub op_edit_done { # PktOp
+        my ($lss, $lei) = @_;
+        eval { _edit_done($lss, $lei) };
+        $lei->fail($@) if $@;
+}
+
+sub lei_edit_search {
+        my ($lei, $out) = @_;
+        my $lss = PublicInbox::LeiSavedSearch->up($lei, $out) or return;
+        do_edit($lss, $lei);
+}
+
 *_complete_edit_search = \&PublicInbox::LeiUp::_complete_up;
 
 1;
diff --git a/lib/PublicInbox/LeiSavedSearch.pm b/lib/PublicInbox/LeiSavedSearch.pm
index fd51fe38..8ceaaf01 100644
--- a/lib/PublicInbox/LeiSavedSearch.pm
+++ b/lib/PublicInbox/LeiSavedSearch.pm
@@ -14,7 +14,7 @@ use PublicInbox::Spawn qw(run_die);
 use PublicInbox::ContentHash qw(git_sha);
 use PublicInbox::MID qw(mids_for_index);
 use Digest::SHA qw(sha256_hex);
-my $LOCAL_PFX = qr!\A(?:maildir|mh|mbox.+|mmdf|v2):!i; # TODO: put in LeiToMail?
+our $LOCAL_PFX = qr!\A(?:maildir|mh|mbox.+|mmdf|v2):!i; # TODO: put in LeiToMail?
 
 # move this to PublicInbox::Config if other things use it:
 my %cquote = ("\n" => '\\n', "\t" => '\\t', "\b" => '\\b');
@@ -29,6 +29,14 @@ sub BOOL_FIELDS () {
         qw(external local remote import-remote import-before threads)
 }
 
+sub cfg_dump ($$) {
+        my ($lei, $f) = @_;
+        my $ret = eval { PublicInbox::Config->git_config_dump($f, $lei->{2}) };
+        return $ret if !$@;
+        $lei->err($@);
+        undef;
+}
+
 sub lss_dir_for ($$;$) {
         my ($lei, $dstref, $on_fs) = @_;
         my @n;
@@ -56,7 +64,7 @@ sub lss_dir_for ($$;$) {
                 for my $g ("$n[0]-*", '*') {
                         my @maybe = glob("$lss_dir$g/lei.saved-search");
                         for my $f (@maybe) {
-                                $c = PublicInbox::Config->git_config_dump($f);
+                                $c = cfg_dump($lei, $f) // next;
                                 $o = $c->{'lei.q.output'} // next;
                                 $o =~ s!$LOCAL_PFX!! or next;
                                 @st = stat($o) or next;
@@ -80,9 +88,9 @@ sub list {
                 print $fh "\tpath = ", cquote_val($p), "\n";
         }
         close $fh or die "close $f: $!";
-        my $cfg = PublicInbox::Config->git_config_dump($f);
+        my $cfg = cfg_dump($lei, $f);
         unlink($f);
-        my $out = $cfg->get_all('lei.q.output') or return ();
+        my $out = $cfg ? $cfg->get_all('lei.q.output') : [];
         map {;
                 s!$LOCAL_PFX!!;
                 $_;
@@ -105,7 +113,7 @@ sub up { # updating existing saved search via "lei up"
         output2lssdir($self, $lei, \$dir, \$f) or
                 return $lei->fail("--save was not used with $dst cwd=".
                                         $lei->rel2abs('.'));
-        $self->{-cfg} = PublicInbox::Config->git_config_dump($f);
+        $self->{-cfg} = cfg_dump($lei, $f) // return $lei->fail;
         $self->{-ovf} = "$dir/over.sqlite3";
         $self->{'-f'} = $f;
         $self->{lock_path} = "$self->{-f}.flock";
@@ -267,7 +275,7 @@ sub output2lssdir {
         my $dir = lss_dir_for($lei, \$dst, 1);
         my $f = "$dir/lei.saved-search";
         if (-f $f && -r _) {
-                $self->{-cfg} = PublicInbox::Config->git_config_dump($f);
+                $self->{-cfg} = cfg_dump($lei, $f) // return;
                 $$dir_ref = $dir;
                 $$fn_ref = $f;
                 return 1;
@@ -275,63 +283,6 @@ sub output2lssdir {
         undef;
 }
 
-sub edit_begin {
-        my ($self, $lei) = @_;
-        if (ref($self->{-cfg}->{'lei.q.output'})) {
-                delete $self->{-cfg}->{'lei.q.output'}; # invalid
-                $lei->err(<<EOM);
-$self->{-f} has multiple values of lei.q.output
-please remove redundant ones
-EOM
-        }
-        $lei->{-lss_for_edit} = $self;
-}
-
-sub edit_done {
-        my ($self, $lei) = @_;
-        my $cfg = PublicInbox::Config->git_config_dump($self->{'-f'});
-        my $new_out = $cfg->{'lei.q.output'} // '';
-        return $lei->fail(<<EOM) if ref $new_out;
-$self->{-f} has multiple values of lei.q.output
-please edit again
-EOM
-        return $lei->fail(<<EOM) if $new_out eq '';
-$self->{-f} needs lei.q.output
-please edit again
-EOM
-        my $old_out = $self->{-cfg}->{'lei.q.output'} // '';
-        return if $old_out eq $new_out;
-        my $old_path = $old_out;
-        my $new_path = $new_out;
-        s!$LOCAL_PFX!! for ($old_path, $new_path);
-        my $dir_old = lss_dir_for($lei, \$old_path, 1);
-        my $dir_new = lss_dir_for($lei, \$new_path);
-        return if $dir_new eq $dir_old; # no change, likely
-
-        ($old_out =~ m!\Av2:!i || $new_out =~ m!\Av2:!) and
-                return $lei->fail(<<EOM);
-conversions from/to v2 inboxes not supported at this time
-EOM
-
-        return $lei->fail(<<EOM) if -e $dir_new;
-lei.q.output changed from `$old_out' to `$new_out'
-However, $dir_new exists
-EOM
-        # start the conversion asynchronously
-        my $old_sq = PublicInbox::Config::squote_maybe($old_out);
-        my $new_sq = PublicInbox::Config::squote_maybe($new_out);
-        $lei->puts("lei.q.output changed from $old_sq to $new_sq");
-        $lei->qerr("# lei convert $old_sq -o $new_sq");
-        my $v = !$lei->{opt}->{quiet};
-        $lei->{opt} = { output => $new_out, verbose => $v };
-        require PublicInbox::LeiConvert;
-        PublicInbox::LeiConvert::lei_convert($lei, $old_out);
-
-        $lei->fail(<<EOM) if -e $dir_old && !rename($dir_old, $dir_new);
-E: rename($dir_old, $dir_new) error: $!
-EOM
-}
-
 # cf. LeiDedupe->has_entries
 sub has_entries {
         my $oidx = $_[0]->{oidx} // die 'BUG: no {oidx}';
diff --git a/script/lei b/script/lei
index 99d94b4e..2d84487a 100755
--- a/script/lei
+++ b/script/lei
@@ -127,6 +127,8 @@ while (1) {
                 last;
         } elsif ($buf =~ /\Achild_error ([0-9]+)\z/) {
                 $x_it_code ||= $1 + 0;
+        } elsif ($buf eq 'wait') {
+                $sigchld->();
         } else {
                 $sigchld->();
                 die $buf;
diff --git a/t/lei-q-save.t b/t/lei-q-save.t
index 743a7b70..9c17a011 100644
--- a/t/lei-q-save.t
+++ b/t/lei-q-save.t
@@ -215,5 +215,22 @@ test_lei(sub {
                 'absolute path appears in ls-search';
         lei_ok qw(up ../s -C), "$home/v2s", \'relative lei up';
         lei_ok qw(up), "$home/s", \'absolute lei up';
+
+        # mess up a config file
+        my @lss = glob("$home/" .
+                '.local/share/lei/saved-searches/*/lei.saved-search');
+        my $out = xqx([qw(git config -f), $lss[0], 'lei.q.output']);
+        xsys($^X, qw(-i -p -e), "s/\\[/\\0/", $lss[0])
+                and xbail "-ipe $lss[0]: $?";
+        lei_ok qw(ls-search);
+        like($lei_err, qr/bad config line.*?\Q$lss[0]\E/,
+                'git config parse error shown w/ lei ls-search');
+        lei_ok qw(up --all), \'up works with bad config';
+        like($lei_err, qr/bad config line.*?\Q$lss[0]\E/,
+                'git config parse error shown w/ lei up');
+        xsys($^X, qw(-i -p -e), "s/\\0/\\[/", $lss[0])
+                and xbail "-ipe $lss[0]: $?";
+        lei_ok qw(ls-search);
+        is($lei_err, '', 'no errors w/ fixed config');
 });
 done_testing;